In nusach Sefard siddurim, there are pronounced differences between nearly every one, each reflecting the particular view of its author as to how to properly reconcile the Arizal with nusach Ashkenaz.
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[Edit: According to Nusach Edot HamMizrach,] why does the Mussaf prayer on Shabbat and Rosh Chodesh include a description of the actual mussaf sacrifice, while the Mussaf prayer on Moed does not? Why ...